相关论文: Thermal Conductivity of Segmented Nanowires
Thermal phonon transport in square- and triangular-lattice Si phononic crystal (PnC) nanostructures with a period of 300 nm was investigated by measuring the thermal conductivity using micrometer-scale time-domain thermoreflectance. The…
The new regime of low-temperature heat transfer in suspended nanowires is predicted. It takes place when (i) only ``acoustic'' phonon modes of the wire are thermally populated and (ii) phonons are subject to the effective elastic…
Phonon properties of small Si nanowires in [110] direction have been analyzed using density functional perturbation theory. Several samples with varying diameters ranging from 0.38 to 1.5 nm have been calculated. It is found that the…
We compute atomistically the heat conductance for ultra-thin pristine silicon nanowires (SiNWs) with diameters ranging from 1 to 5 nm. The room temperature thermal conductance is found to be highly anisotropic: wires oriented along the…
Nanostructured silicon is a promising material for thermoelectric conversion, because the thermal conductivity in silicon nanostructures can be strongly reduced with respect to that of bulk materials. We present thermal conductivity…
Porous materials provide a large surface to volume ratio, thereby providing a knob to alter fundamental properties in unprecedented ways. In thermal transport, porous nanomaterials can reduce thermal conductivity by not only enhancing…
A mathematical model is presented for thermal transport in nanowires with rectangular cross sections. Expressions for the effective thermal conductivity of the nanowire across a range of temperatures and cross-sectional aspect ratios are…
We study heat current autocorrelation function and thermal conductivity in core-shell nanowires by using molecular dynamics simulations. Interestingly, a remarkable oscillation effect in heat current autocorrelation function is observed in…
In recent years, nanostructuring of dielectric and semiconducting crystals has enhanced controllability of their thermal conductivity. To carry out computational material search for nanostructured materials with desirable thermal…
We determine the size effect on the lattice thermal conductivity of nanoscale wire and multilayer structures formed in and by some typical semiconductor materials, using the Boltzmann transport equation and focusing on the Knudsen flow…
We study arrays of parallel doped semiconductor nanowires in a temperature range where the electrons propagate through the nanowires by phonon assisted hops between localized states. By solving the Random Resistor Network problem, we…
This review summarizes recent studies of thermal transport in nanoscaled semiconductors. Different from bulk materials, new physics and novel thermal properties arise in low dimensional nanostructures, such as the abnormal heat conduction,…
Phonon polaritons have attracted increasing interest as a means to offset the reduction in phonon thermal conductivity in nanostructures caused by enhanced boundary scattering. However, the interpretation of the limited experimental data on…
A semi-analytical model for studying thermal transport at the nanoscale, able to accurately describe both the effect of out of equilibrium transport and the thermal transfer at interfaces, is presented. Our approach is based on the…
Knowledge of the mean free path distribution of heat-carrying phonons is key to understanding phonon-mediated thermal transport. We demonstrate that thermal conductivity measurements of thin membranes spanning a wide thickness range can be…
The lattice thermal conductivity of crystalline Si nanowires is calculated. The calculation uses complete phonon dispersions, and does not require any externally imposed frequency cutoffs. No adjustment to nanowire thermal conductivity…
Nanostructuring on length scales corresponding to phonon mean free paths provides control over heat flow in semiconductors and makes it possible to engineer their thermal properties. However, the influence of boundaries limits the validity…
We find that introducing segmented isotopic disorder patterns may considerably reduce the thermal conductivity of pristine carbon nanotubes below the uncorrelated disorder value. This is a result of the interplay between different length…
Suppressing phonon propagation in nanowires is an essential goal towards achieving efficient thermoelectric devices. Recent experiments have shown unambiguously that surface roughness is a key factor that can reduce the thermal conductivity…
We have performed thermal conductance measurements on individual single crystalline silicon suspended nanowires. The nanowires (130 nm thick and 200 nm wide) are fabricated by e-beam lithography and suspended between two separated pads on…